The present invention is a method and system for testing the reliability of an object such as a satellite prior to deployment, and more particularly provides a method and system for subjecting the object to high intensity acoustic energy by assembling an acoustic system about the object rather than transporting the object to location for performing such acoustic testing. Moreover, the present invention also provides for performing other types of tests without transporting the object. In particular, the present invention provides for performing mechanical vibration tests on the object in the same location as the acoustic testing of the object is performed.
In the manufacturing assembly of objects, such as satellites, that are subject to extreme conditions during operation, various types of qualification or certification testing are typically performed on the object to determine whether the object can withstand the extreme conditions and still perform its intended functions. For example, it may be desirable to perform high energy acoustic tests of the object (e.g., a satellite) to determine whether various components of the object can withstand a high energy acoustic environment and still perform adequately. In particular, such acoustic testing is desirable for high surface area and low mass components such as solar panels. Moreover, it may also be desirable to perform other types of tests such as mechanical vibration tests on such objects.
Heretofore, to acoustically test an object such as a satellite prior to launch, the satellite would be transported to a specially configured reverberant acoustic chamber for subjecting the satellite to a uniform high energy acoustic environment. The transportation of the satellite is time consuming, expensive, and subjects the satellite to risks that are preferably avoided. Accordingly, it would be advantageous to perform high energy acoustic testing using a transportable acoustic system that can be assembled about the satellite without requiring the satellite to be moved. Moreover, it would be also be advantageous to provide a plurality of different types of qualification or certification tests to an object such as a satellite without moving the satellite between a plurality of testing stations. In particular, it would be advantageous to provide acoustic testing and mechanical vibration testing without the necessity of moving the satellite between various testing stations.
The present invention is a method and system for performing acoustic testing of a test object, such as a satellite, for thereby determining whether the test object is able to properly function when and/or after being subjected to high intensity acoustic energy. In particular, the present invention provides a method and system for at least partially surrounding the test object with high output acoustic speakers for directing acoustic energy directly at the test object for a specific desired range of test frequencies and corresponding decibel levels.
Prior to performing such an acoustic test, the present invention also provides a method for acoustically calibrating the speaker outputs so that the desired frequency range and corresponding decibels are achieved substantially uniformly about the test object. In particular, the speakers together with microphones for monitoring speaker acoustic output, are configured in initial positions around the test object. The speakers are expected to yield an approximately uniform acoustic distribution about the test object and the microphones are distributed around and substantially near the test object for measuring the acoustics impacting the test object. Accordingly, for each of a plurality of desired and/or predetermined acoustic frequencies and corresponding decibel levels, it is an aspect of the present invention to use the measurements obtained from the microphones to:
(a) determine whether the frequencies and corresponding decibel levels can be achieved by the speakers and related acoustical components (e.g., amplifiers) for electrically driving and controlling the acoustic output of the speakers;
(b) electronically and/or physically adjust the speaker outputs for obtaining a substantially uniform acoustic pressure about at least the portion of the test object identified as most vulnerable to a malfunction induced by the impact of high acoustic energy; and
(c) further adjust the speaker outputs and/or provide additional modifications to the acoustical environment for alleviating or reducing localized acoustical anomalies such as resonance build-ups.
Thus, a result of the calibrating of the speaker outputs is that during actual testing of the test object, various speakers may be powered at different levels and, the speakers will be oriented so as to output a substantially uniform acoustic that varies substantially no more than, e.g., 6 dB about the test object.
Moreover, it is an aspect of the present invention to provide an acoustic environment altering material to the enclosure within which the acoustic calibration and testing is being performed so that an appropriate acoustic pressure level impacts the test object. In particular, it is an object of the present invention that a substantial amount of the acoustic energy output by the speakers directly impact the test object at a substantially normal angle to a surface of the test object. More particularly, when a satellite is the test object, it is an aspect of the present invention that such substantially normal acoustic impact be directed at high volume, low density portions of the satellite such as solar panels since these components are more likely to malfunction from high energy acoustics than other components. Accordingly, to reduce acoustic reflections and deflections, the acoustic altering material may be provided on the interior surface of the enclosure for dampening such reflected and/or deflected acoustic waves. Moreover, note that such dampening material may also reduce the intensity of localized relatively high energy acoustic build-ups in locations that might damage the test object as mentioned in (c) above.
Additionally, regarding (c) above, the present invention mitigates both high intensity and low intensity isolated acoustic anomalies substantially near the test object (wherein such anomalies might compromise what would otherwise be considered a substantially uniform acoustic test of the test object) by optionally providing partitions or other devices for directing or restricting a direction of the acoustic energy generated by the speakers.
Moreover, it is an aspect of the present invention that the speakers may be positioned at various distances and orientations from the test object. In particular, such speakers may be provided upon pedestals and/or at different heights relative to the test object. In particular, such speakers may be suspended as well as floor mounted for providing a plurality of acoustic sources that may generally hemispherically surround the test object.
It is also an aspect of the present invention that the test object may be acoustically tested without moving the test object from its area of manufacture since the acoustic generating portions of the present invention may be conveniently transported and positioned about the test object. Accordingly, the present invention may be used in place of transporting the test object to a specially engineered reverberant chamber for acoustically testing objects in a uniform acoustic environment having a very narrow acoustic variation between locations within the chamber.
Additionally, it is an aspect of the present invention that a plurality of different diagnostic or qualification tests can be performed without transporting the test object. In particular, mechanical vibration testing may be performed concurrently or serially with the acoustic testing of the present invention without transporting the test object.
Other features and benefits of the present invention will become evident from the accompanying drawings and the detailed description hereinbelow.